Marine engine muffler



H. s. VAUGHN MARINE ENGINE IVIUFF'LER Filed Jan. s, 1961 MMV-.L w

IN V EN TOR.

Nov. 19, 1963 United States Patent 3,111,190 MARENE ENGINE MUFBLER Hubert S. Vaughn, 1042 N. Center St., Corry, Pa. Filed Jan. 3, 1961, Ser. No. 80,210 3 Claims. (Cl. 181-52) In marine engines, Ithe engine cooling water and the exhaust gases are conducted to the stern of the boat through an exhaust pipe. The ydischarge is above the surface of the water Iand the noise is substantial. This invention is a muiiler which may be inserted in the exhaust pipe to reduce the noise without objectionable increase in back pressure.

In the accompanying drawing, PIG. 1 is a longitudinal section on line 1--1 of FIG. 3 through an exhaust pipe equipped with a muiiler, FIG. 2 is la side view of the muier unit, and 'Fl-G. 3 is an end view of the muiiier unit.

The exhaust pipe 1 carries` both the engine cooling water and the exhaust 'gases from the engine to` lthe stern of the boat where it discharges above the surface of the water. `In the conventional exhaust pipe, the cooling water flows along the lower part of the exhaust pipe as indicated at 2.

In order to reduce the noise level, there is inserted in the exhaust pipe a muler section of the same diameter as the pipe. lThis is advantageous when a muffler is to be linstalled in an old boat. For new boats, the mutiler could be made as a separate section to be connected at a convenient point between the inlet and loutlet ends of the exhaust pipe. i l

The muiiier comprises of plurality of axially spaced bands or rings 3, 4, 5, 6, 7 suitably connected to upper and lower longtiudinally extending rods 8, 9. This provides an assembly which can be assembled into an exhaust pipe, -for example by yinsertingv it into the outlet or discharge end of lthe pipe. t

Each of the rings carries a plurality of vertically spaced vanes 10. In the rings 3 and 5, the vanes 1t) are inclined upwardly while in bands 4, 6 and 7, the vanes are inclined downwardly. At the entrance tothe muffler section, the varies 10 in the ring 3 deflect the cooling water and exhaust gas upwardly as indicated by arrows 11. The upwardly deflected mixture passing through the band 3 is `alternately deilected downward as indicated by arrow 12, upward as indicated by arrow 13, and again downward as indicated by arrow 14 as it passes through the rings 4, and 6.

In rings 3 and S, the lowermost vane 10 is close to the lower surface land in rings 4 and 6 the uppermost vane 1 8 is close to the upper surface of the pipe so substantially all of the mixture is subjected to the deiieoting and mixing action of the varies. The vanes deflect the water and exhaust gases transversely to the general direction of low, iirst in one direction and then in the opposite direction, and fthe resultant effect is to mix the water and exhaust gases so that upon passing through the ring 6, the mixture is almost like a fog. At this point, the

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exhaust gas noises of the motor are reduced to such an extent that other engine noises (ie. valve tappets, etc.) become noticeable.

The exhaust gases could be discharged directly to the atmosphere after passing through the ring 6 but the foglike discharge is sometimes objectionable. The fog is decreased to a tolerable amount by passing the fog through the ring 7 where the vanes 10 are downwardly inclined. This last stage does not have any quieting effect but it does cause the heavier particles of the fog to combine into drops so as to eliminate the objectionable fog effect.

Part of the reduction in 'noise is due vto the intimate mixing of the exhaust gases and cooling water which both cools the exhaust gases and attenuates the noise. This is accomplished in a very short section of the same diameter as the exhaust pipe. The length of the quieting section of the muffler (rings 3 to y6 inclusive) can be as little as tive times Ithe diameter of the exhaust pipe.

As with all muiilers, there is some increase in engine back pressure, but the elect is negligible, possibly due to the cooling of the exhaust gases by the engine cooling water and the consequent reduction in volume.

What is claimed yas new is:

1. For use with a marine engine having a horizontal exhaust pipe carrying the engine cooling water and exhaust gases, said pipe having a series of uniplanar vanes within'the same and spaced axially from each other along the pipe, alternate of the va-nes in the series extending upwardly and outwardly to deflect the cooling water and exhaust gases upwardly and outwardly and the other of the vanes in the series extending downwardly and outwardly to deflect .the cooling water and exhaust gases downwardly and outwardly.

2. The structure of claim 1 in which the outlet of the exhaust pipe is above water and additional vanes are provided in the section of pipe prior to the outlet to deflect the exhaust gases and cooling water downward.

3. The structure of claim 1 in which the vanes are carried in a plurality of axially spaced rings itting inside the exhaust pipe and members extend axially between the rings and connect the rings into an assembly which may be inserted into the pipe.

References Cited in the le of this patent UNITED STATES PATENTS 213,348 Richardson Mar. 18, 1879 1,048,435 Still Dec. 24, 1912 1,065,707 Montgomery lune 24, 1913 1,131,862 Perkins Mar. 16, 1915 1,182,611 Williams etal May 9, 1916 1,478,948 Gara Dec. 25, 1923 FOREIGN PATENTS 281,808 Great Britain Dec. 15, 1927 536,848 Germany Oct. 28, 1931 

1. FOR USE WITH A MARINE ENGINE HAVING A HORIZONTAL EXHAUST PIPE CARRYING THE ENGINE COOLING WATER AND EXHAUST GASES, SAID PIPE HAVING A SERIES OF UNIPLANAR VANES WITHIN THE SAME AND SPACED AXIALLY FROM EACH OTHER ALONG THE PIPE, ALTERNATE OF THE VANES IN THE SERIES EXTENDING UPWARDLY AND OUTWARDLY TO DEFLECT THE COOLING WATER AND EXHAUST GASES UPWARDLY AND OUTWARDLY AND THE OTHER OF 